#include<stdio.h>
int f(int b[][4])
{
    int i,j,s=0;
    for(j=0;j<4;j++)
        {
            i=j;
            if(i>2)
            i=3-j;
            s+=b[i][j];
        }
        return s;
}
int main()
{
    int a[4][4]={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};
    printf("%d\n",f(a));
    return 0;
}